Pattern-Effect Reduction Using a Cross-Gain Modulated Holding Beam in Semiconductor Optical In-Line Amplifier

A novel structure composed of two semiconductor optical amplifiers (SOA) designed to amplify a signal within an optical link is proposed. It is based on the use of a cross-gain modulated holding beam (HB) to reduce the undesirable data pattern-dependent wandering of the amplified signal that is commonly observed in straightforward single-device amplifiers. Using an advanced simulator, patterning of amplified 100-Gb/s pseudorandom bit sequences is minimized in terms of HB input power. A comparison between the proposed scheme and a straightforward amplifier shows outperformance of the former by more than 50% at the expense of 4.1 dB of amplification penalty. The numerical investigations also show inconsequential degradation of the signal extinction ratio. The proposed structure represents a compact alternative to readily reduce patterning in SOA-based high-speed optical communication systems